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Transcript
Institute of Astronomy
PUBLIC OPEN EVENING
— 18 February 2015 —
I really don’t know clouds at all:
Mars’ giant plumes still a mystery
PAST observations of strange plumes
of material on Mars are proving a
problem to explain.
In March and April 2012, amateur
astronomers reported observing a
towering plume of gas stretching up
to altitudes over 250 km, well into
the thin upper reaches of the Martian
atmosphere.
Each time the plume took less than
10 hours to develop, and then persisted for about 10 days before fading
away. Both plumes occurred above the
same region of the Martian surface;
what they are and how they were
caused remain ambiguous.
One explanation is that they are
simply large reflective clouds of wateror carbon dioxide-ice mixed with dust
particles. However, this does not fit
with previous observations of cloud
features that remain below 100 km.
Alternatively, the plumes could
be some kind of aurora (i.e. Martian
“Northern Lights”) caused by anomalies in the surface magnetic field.
Although auroral lights have been
observed before in this spot, they have
always been a thousand times fainter.
So the mystery remains—perhaps
until a canny amateur is able to catch
the next plume forming.
outreach
A
TONIGHT’S SPEAKERS
Zephyr Penoyre & The CHaOS Crew
Building a universe in a year
Our weekly welcome
W
The March 2012 sighting of a mysterious
high-altitude plume on Mars (circled) and its
evolution. Image: W. Jaeschke & D. Parker
18 new odd-couple stars with age, mass gap
ASTRONOMERS have discovered very mismatched binary stars, where one star
is shining while the other has yet to finish forming.
The Sun is unusual in being a singleton, as most stars are born in pairs. The
majority of such “binary” stellar systems comprise companions of equal mass,
but maybe that is not always the case.
Mismatched pairs are hard to find—a very massive star will easily outshine a
smaller companion and hide its presence. The 18 newly discovered systems were
only identified by the way the smaller star moved between us and its massive
companion, blocking some of the latter’s light to cause a slight eclipse.
The stars in the new systems exhibit extreme differences in mass (the heavier
star weighs in at 6–16 solar masses, with its partner at 1–2 solar masses), and
circle each other very tightly with orbits lasting only 3–9 days.
Even stranger, anomalies in the signal of the eclipse show that the fainter
and less massive object is not yet a fully formed star. The more massive star has
somehow formed while the other is still contracting under gravity.
The excitement of discovering such systems lies in the way they may tell us
how massive stars in binaries can form and evolve.
HAT if the Universe were built
in just one year? Allow the
CHaOS Science Roadshow to illustrate with hands-on demonstrations,
plenty of crashes and explosions,
and one very large clock.
This special presentation begins
as usual at 7.15pm, and will be followed by an opportunity to observe
if (and only if…) the weather is clear.
The IoA’s historical Northumberland and Thorrowgood telescopes
will be open for unaided-eye
observations, and we will be staffing
some smaller telescopes around the
observatory lawns.
The Cambridge Astronomical
Association will also provide an outdoors floorshow relaying live images
from three modern telescopes, with
commentary.
If we’re unlucky and it’s cloudy,
then we’ll offer you a cup of tea as
compensation, and the CAA will
offer some more astro-information
afterwards in the lecture theatre for
those who want to stay on.
We tweet current astro-news and events
as IoACOA. Please e-mail any questions,
comments or suggestions about the IoA
Public Open Evenings to Carolin Crawford
at [email protected]
www.ast.cam.ac.uk/public
WHAT YOU CAN LOOK FORWARD TO:
⊕ A series of half-hour astro-talks in our lecture theatre
� Posters, displays, demonstrations and activities all
around the site, for everyone to learn more about
astronomy and the kind of research we do
⊕ Our librarian Mark will showcase some of the rare and
unique astro-gems to be found in our historical library
� If you’re a Dr Who fan, then come along and meet the
15th Cyber Legion
⊕ The Cambridge Science Centre will bring along some
of their hands-on displays from their forthcoming
Explore the Universe exhibition
� Meteorites to examine and purchase from our friends
at Spacerocks UK
⊕ A glass art exhibition in one of the telescope domes
� Visit the historical telescopes on site and see what they
look like in daylight
⊕ Our Starlite cafe will provide tea and snacks, as well as a
chance to rest your feet
� The CAA will offer family make-and-do activities, and
showcase a range of amateur telescopes
Please note that this year we are not offering observing in the evening
Other astro-events
to put in your diary
20 MAR: SOLAR ECLIPSE VIEWING
20 FEB: GAIA MISSION UPDATE
The IoA’s Heather Campbell will give
an update on the Gaia satellite mission
this Friday 20th February.
The talk will be held in the Sackler
Lecture Theatre at the IoA, and starts
at 8pm. Everyone is welcome.
16–21 MAR: GLASS ART EXHIBITION
Glass artist Livvy Fink will be exhibiting some of her artwork (right) at the
IoA on 16th–21st March.
These pieces were inspired by an
ongoing collaboration between the IoA
and Cancer Research UK; they explore
the relationship between macro-structures and micro-structures, and the
sense of wonder they both provoke.
The artwork captures impressions of
unfamiliar worlds inspired by the most
distant galaxies and the cells within
us, where light is diffused through a
myriad of intricate surfaces suspended
within glass.
The IoA and CAA are combining forces
to celebrate the solar eclipse occurring
on the morning of Friday 20th March.
A solar eclipse occurs when the
Moon passes between us and the Sun,
casting a shadow on the Earth’s surface.
From Cambridge the eclipse will be
partial, but at maximum coverage the
Moon will obscure a whopping 85% of
the Sun. This is the only chance to see a
major eclipse here for several years.
The eclipse will last from 8.26am to
10.43am. We shall provide a series of
short talks at the IoA, and hope to relay
a live feed from locations where the
event will appear as a total eclipse.
If the weather is clear, we will also
open up the telescopes at the Observatory for safe viewing of the eclipse.